Turning Tool Angle Correction for Accurate Multi-Axis Machining

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Solution Overview

Problem

Conventional turning methods in CNC processing machines face limitations in accurately correcting tolerance-related position deviations, especially in operations with a higher number of degrees of freedom, due to dimensional and shape deviations of tools and machining processes.

Innovation Solution

A method and computer program that allow for the measurement and correction of tolerance-related position deviations by varying the angle of attack of the tool holder, using correction data measured at multiple angles to compensate for positional deviations in real-time, enabling dimensionally accurate workpieces even in operations with changing angles of attack without altering the tool.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If correction values are measured only in conventional directions (less than 1 mm fine correction), then the measurement process remains simple, but the correction reliability is insufficient for turning operations with larger number of degrees of freedom

Engineering Contradiction:
Improvecorrection reliabilityVSAvoidmeasurement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extends the correction measurement from conventional two-dimensional orthogonal directions to three-dimensional spherical coordinates (radial distance r, polar angle θ, azimuthal angle φ). This dimensional expansion enables comprehensive correction of tool position deviations in all spatial directions, significantly improving correction reliability for multi-degree-of-freedom turning operations while maintaining measurement feasibility through systematic angular discretization

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the angle of attack is varied to improve machining versatility, then the adaptability of turning operations increases, but the tolerance-related position deviations become more difficult to correct

Engineering Contradiction:
Improvemachining adaptabilityVSAvoidposition deviation correction
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent performs comprehensive measurement and determination of correction values for all possible angles of attack before actual machining operations. By pre-calculating correction values for the entire range of angles (θ from 0° to 180°, φ from 0° to 360°), the system ensures that accurate correction data is available for any angle of attack selected during machining, thereby maintaining manufacturing precision while enabling machining versatility

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent systematically varies the angular parameters (θ and φ) to define multiple measurement directions in spherical coordinates. By measuring tool position deviations along different angular directions and interpolating results, the system determines accurate correction values for any angle of attack, thus maintaining manufacturing precision while accommodating varied machining adaptability

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If correction values are determined for all possible angles of attack, then the correction accuracy improves, but the measurement and data processing time increases

Engineering Contradiction:
Improvecorrection accuracyVSAvoidmeasurement time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent measures correction values at a finite number of discrete angular positions (θ_i from 0° to 180°, φ_j from 0° to 360°) rather than continuously for all possible angles. This partial sampling approach, combined with interpolation between measured points, achieves sufficient correction accuracy while significantly reducing measurement and data processing time compared to exhaustive measurement

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4371684A1Method for turning
Publication Date: 2024.05.22 CERATIZIT AUSTRIA GES
  • EP4371684A1 patent drawingFigure 1~2
  • EP4371684A1 patent drawingFigure 3~5
  • EP4371684A1 patent drawingFigure 6a~6b

AI summary

A method for turning operations in a machine tool is provided with a tool (100) comprising a tool holder (1) held in a machine-side receptacle with an interchangeable cutting insert (2) attached thereto, which has at least one cutting edge section (22; 22'; 22") usable for turning a workpiece (W) rotating about an axis of rotation (Z) with at least one rounded cutting corner region (22a) and at least one straight first cutting edge region (22b) adjoining this cutting corner region (22a), such that an angle of attack (κ) which the first cutting edge region (22b) encloses with the axis of rotation (Z) of the workpiece (W) is varied by rotating the tool holder (1) about its longitudinal axis (L) or an axis parallel thereto.Correction data (Δx, Δy, Δz, Δr), which represent tolerance-related positional deviations of the cutting edge section (22; 22'; 22"), are individually measured for a plurality of different approach angles (κ) and the control of the tool (1) during turning is corrected based on the correction data (Δx, Δy, Δz, Δr) depending on the approach angle (κ).